Can't get a solid gradient

This is driving me crazy! I cannot get photoshop to create a solid gradient fill. Every time I fill with the gradient tool, the gradient is about 90% opacity. I choose a solid gradient from the basic folder, I then select the colors I want (to replace the black and white foreground/background colors) and when I fill the selected area, the gradient is always about 90% opacity. I have the gradient tool set to normal blend mode, 100% opacity and method :classic. Still 90% opacity!!??. Is there some other setting I am missing? (note, if I don't replace the black and white foreground and background colors of the basic gradient and just leave them black and white, the gradient will be solid (100% opacity)